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Texas Instruments LP3985IBPX-3.1/NOPB
- Part No.:
- LP3985IBPX-3.1/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 5-WFBGA, DSBGA
- Datasheet:
-
LP3985IBPX-3.1/NOPB.pdf
- Description:
- IC REG LINEAR 3.1V 150MA 5DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:2,787
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Product details
Overview
LP3985IBPX-3.1/NOPB from Texas Instruments (formerly National Semiconductor) is a micropower, ultra-low-noise, ultra-low-dropout CMOS LDO voltage regulator delivering 3.1V at up to 150mA from a 2.5V–6.0V input. It features 30µVrms output noise (10Hz–100kHz), ≤100mV dropout at full load, and 1.5µA shutdown current - optimized for battery-powered RF and analog signal chains in mobile handsets.
For engineers reviewing the LP3985IBPX-3.1/NOPB datasheet, LP3985IBPX-3.1/NOPB pinout, LP3985IBPX-3.1/NOPB application, or LP3985IBPX-3.1/NOPB equivalent, key selection criteria include low-noise performance in compact micro SMD packaging, fast 200µs turn-on time with internal bypass pre-charge, thermal/short-circuit protection, and compatibility with 1µF ceramic output capacitors.
Technical Context
The LP3985IBPX-3.1/NOPB employs a CMOS pass transistor architecture enabling ultra-low quiescent current and minimal dropout across its operating range. Its bandgap reference includes an internal 70µA pre-charge current source for the BYPASS pin, decoupling noise reduction from transient response speed.
Power supply rejection exceeds 50dB at 1kHz under VIN = VOUT + 0.2V conditions and remains effective down to low input voltages typical of discharging Li-ion batteries. Stability is guaranteed with 1µF ±30% X7R ceramic output capacitors and no minimum load requirement.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.1V ±3% - precision-regulated rail for RF ICs or low-voltage logic requiring tight tolerance. |
| Max Output Current | 150mA guaranteed - sufficient for GSM/CDMA transceiver bias, audio codecs, or sensor interfaces. |
| Dropout Voltage | ≤100mV at 150mA - enables operation down to ~3.2V input while maintaining regulation on 3.1V rail. |
| Output Noise | 30µVrms (10Hz–100kHz) - low enough for sensitive RF front-ends and high-resolution ADC references. |
| Quiescent Current | 85µA typical at 1mA load - extends battery life in always-on standby circuits. |
| Shutdown Current | ≤1.5µA - enables deep-sleep modes in portable devices without external disconnect switches. |
| PSRR @ 1kHz | ≥50dB at VIN = VOUT + 0.2V - suppresses switching noise from PMICs or DC-DC converters feeding the LDO input. |
| Operating Temp | −40°C to +125°C junction - qualified for automotive infotainment and industrial handheld environments. |
Pinout & Package
LP3985IBPX-3.1/NOPB uses a 5-bump micro SMD package (NS Package BPA05, 0.170mm bump height). Total footprint is <2.0mm × 2.5mm - smaller than 1206 passive components. The package is JEDEC-compliant with non-solder-mask-defined (NSMD) pads and requires UV-protective PCB layout due to light sensitivity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VEN (A1) | Logic-controlled enable input | Active-high control: VIH ≥1.4V, VIL ≤0.4V - compatible with 1.8V/3.3V GPIO; tie to VIN for always-on operation. |
| GND (B2) | Common ground reference | Low-impedance return path for all currents; must connect to clean analog ground plane near device. |
| VOUT (C1) | Regulated output terminal | Delivers stable 3.1V; requires 1µF X7R ceramic capacitor placed ≤1cm away with low-ESR (<500mΩ). |
| VIN (C3) | Input voltage supply | Accepts 2.5V–6.0V; needs ≥1µF input capacitor close to pin to suppress source impedance effects. |
| BYPASS (A3) | Noise reduction node | Connects to 0.01µF NPO/COG ceramic capacitor; reduces output noise without degrading load transient response. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low-noise regulation | 30µVrms output noise over 10Hz–100kHz - preserves SNR in RF receivers and precision analog stages. |
| Micro SMD footprint | 0.85mm × 1.41mm body size - minimizes PCB area in space-constrained mobile phone modules. |
| Fast turn-on with pre-charge | 200µs typical startup time - achieved via internal 70µA BYPASS capacitor charger, eliminating external RC delays. |
| Stable with small ceramics | Guaranteed stability using only 1µF ±30% X7R ceramic output capacitor - eliminates need for larger, costly tantalum parts. |
| Robust protection | Thermal shutdown (160°C) and short-circuit current limit (600mA) - prevents damage during fault conditions without external circuitry. |
Applications
| CDMA Cellular Handsets | GSM Cellular Handsets |
|---|---|
Use Scenario: Powering RF transceiver ICs and baseband processors in dual-mode handsets. IC Role / Device Role / Timing Role: Low-noise 3.1V supply for VCOs, PLLs, and mixer bias networks. Use Value: 30µVrms noise prevents phase noise degradation in transmit/receive paths, maintaining EVM and adjacent channel leakage specs. |
Use Scenario: Supplying SIM interface, power amplifier drivers, and audio codec analog sections. IC Role / Device Role / Timing Role: Primary 3.1V LDO for low-power standby and burst transmission modes. Use Value: ≤1.5µA shutdown current extends battery life during idle periods; 100mV dropout allows operation until battery reaches 3.2V. |
| Wideband CDMA Handsets | Portable Information Appliances |
Use Scenario: Delivering clean power to high-speed ADCs/DACs and digital front-end FPGAs. IC Role / Device Role / Timing Role: Local regulation for noise-sensitive mixed-signal subsystems. Use Value: 50dB PSRR at 1kHz rejects ripple from switching PMICs, preserving dynamic range in 12-bit+ data converters. |
Use Scenario: Powering GPS receivers, Bluetooth SoCs, and MEMS sensors in handheld PDAs or medical monitors. IC Role / Device Role / Timing Role: Micropower 3.1V rail for always-on sensing and wake-up logic. Use Value: No-load stability ensures reliable RAM keep-alive during sleep; −40°C to +125°C rating supports outdoor deployment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO voltage regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPL720F31 | 300mA output, 25µVrms noise, 6V max input, same 3.1V fixed output | Higher current capability; slightly lower noise; requires 2.2µF output cap | Preferred when >150mA load margin or tighter noise spec is required; larger SOT-23-5 footprint. |
| MCP1703T-3102E/MB | 250mA output, 40µVrms noise, 16V max input, 3.1V fixed output | Wider input range; higher noise; no BYPASS pin for noise tuning | Suitable for industrial systems with variable input (e.g., 12V rails); lacks micro SMD option and optional noise reduction path. |
Compared with LP3985IBPX-3.1/NOPB, TPL720F31 offers higher current and lower noise but sacrifices the ultra-compact micro SMD form factor; MCP1703T-3102E/MB provides broader input voltage support but lacks the BYPASS-controlled noise optimization and smallest footprint.
Availability
LP3985IBPX-3.1/NOPB is available at Aetrix Electronics and suitable for CDMA/GSM handset design, portable medical instrumentation, and wireless sensor node development requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.
Supply support for LP3985IBPX-3.1/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments acquired National Semiconductor in 2011 and maintains full technical and supply chain continuity for legacy analog products including the LP3985 series.
The LP3985IBPX-3.1/NOPB belongs to TI's ultra-low-noise LDO portfolio designed specifically for battery-powered RF and precision analog applications where board space, power efficiency, and spectral purity are critical.
FAQ
What is the maximum input voltage for LP3985IBPX-3.1/NOPB?
The absolute maximum input voltage for LP3985IBPX-3.1/NOPB is 6.5V, but the recommended operating range is 2.5V to 6.0V. Exceeding 6.0V risks violating the specified electrical characteristics and may trigger internal protection circuits. For sustained reliability, maintain VIN ≤6.0V with appropriate derating for ambient temperature and power dissipation.
Does LP3985IBPX-3.1/NOPB require an external bypass capacitor to function?
No, LP3985IBPX-3.1/NOPB operates fully functional without the BYPASS capacitor. The 0.01µF capacitor connected to the BYPASS pin is optional and serves only to reduce output noise - it does not affect regulation, stability, or transient response. Omitting it increases output noise to ~30µVrms × (3.1/2.5) ≈ 37µVrms, but retains all other specifications including 200µs turn-on time.
Can LP3985IBPX-3.1/NOPB be used with a 0.47µF output capacitor?
No - LP3985IBPX-3.1/NOPB requires a minimum 0.7µF output capacitance for guaranteed stability per the datasheet. A 0.47µF capacitor falls below this threshold and may cause oscillation or poor transient response. Use only 1.0µF ±30% X7R ceramic (or equivalent high-quality tantalum) with ESR between 5mΩ and 500mΩ, placed within 1cm of the VOUT pin.
What is the thermal shutdown behavior of LP3985IBPX-3.1/NOPB?
LP3985IBPX-3.1/NOPB activates thermal shutdown at 160°C junction temperature and includes 20°C hysteresis, meaning it resumes regulation only after cooling to ≤140°C. During shutdown, the output is disabled and quiescent current drops to ≤1.5µA. This protects against sustained overload or poor PCB thermal design without requiring external thermal monitoring circuitry.
Is LP3985IBPX-3.1/NOPB compatible with lead-free reflow processes?
Yes - LP3985IBPX-3.1/NOPB is RoHS-compliant and rated for standard lead-free reflow profiles, including peak temperatures up to 260°C. The micro SMD package (BPA05) requires NSMD pad design and careful stencil aperture sizing per AN-1112. Avoid prolonged exposure above 235°C at the solder pad level, as specified in the Absolute Maximum Ratings.
LP3985IBPX-3.1/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 5-WFBGA, DSBGA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 6V
- Voltage - Output (Min/Fixed):
- 3.1V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.1V @ 150mA
- Current - Output:
- 150mA
- Current - Quiescent (Iq):
- 150 µA
- Current - Supply (Max):
- 250 µA
- PSRR:
- 50dB ~ 40dB (1kHz ~ 10kHz)
- Control Features:
- Enable
- Protection Features:
- Over Current, Over Temperature, Short Circuit
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 5-DSBGA (1.41x1.08)
LP3985IBPX-3.1/NOPB FAQ
1.How can I place an order for LP3985IBPX-3.1/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3985IBPX-3.1/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LP3985IBPX-3.1/NOPB reliable?
The price and inventory of LP3985IBPX-3.1/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3985IBPX-3.1/NOPB is usually 5 days.
3.What payment methods are accepted for LP3985IBPX-3.1/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3985IBPX-3.1/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3985IBPX-3.1/NOPB?
LP3985IBPX-3.1/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3985IBPX-3.1/NOPB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LP3985IBPX-3.1/NOPB?
For technical support, including LP3985IBPX-3.1/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3985IBPX-3.1/NOPB requirements.
6.How does Aetrix verify that LP3985IBPX-3.1/NOPB is sourced from the original manufacturer or authorized distributors?
All LP3985IBPX-3.1/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LP3985IBPX-3.1/NOPB meets industry standards.
7.What is the process for return or replacement of LP3985IBPX-3.1/NOPB?
All LP3985IBPX-3.1/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP3985IBPX-3.1/NOPB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LP3985IBPX-3.1/NOPB part is unused and in its original packaging.
Return procedure for LP3985IBPX-3.1/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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